Experimental and numerical prediction of the local thickness reduction defect of complex cross-sectional steel in cold roll forming

In the cold roll forming process of complex cross-sectional steel, the local thickness reduction is one of the major problems to be solved for increasing requirements regarding tolerances. The prediction of the local thickness reduction during the roll forming process in the bending zones is gaining more and more importance. Based on the elastic plasticity deformation theory, the 3D finite element analysis (FEA) models have been built by the professional software COPPA RF and MSC MARC to simulate the cold roll forming process. Roll forming tests and the local thickness reduction analyses were performed to compare with FEA simulation results. An application to a hat-shaped section profile and the effect of forming parameters on transverse strains and the local thickness reduction are discussed. The linear regression method was applied to evaluate its effect on the local thickness reduction by using Minitab software. Results indicate that the loading pattern and the roll diameter have the greatest impacts on local thickness reduction and transverse strains in the bending regions. The findings were applied to optimize the abatement of local thickness reduction for the novel elevator guide rail roll forming lines. The predicted thickness reduction values in cold roll forming proves in good agreement with experimental results, and the complex cross-sectional steel with high quality is produced.